Existing voltage comparators use high gain operation amplifiers as the active element. A reference voltage and a voltage under consideration are coupled to the inputs of an operation amplifier. When the voltage under consideration is higher than the reference voltage, the output is forced by the high gain operation amplifier to one value (either a high or a low). When the voltage under consideration is lower than the reference voltage, the high gain operation amplifier switches the output to the opposite value. As a result, the output value is indicative of whether the voltage under consideration is higher or lower than the reference voltage.
It is known that high gain operation amplifiers occupy large areas of silicon. Also, the power consumption of operation amplifiers is high. Consequently, it is desirable to have another type of voltage comparators that is smaller, more energy efficient, and runs faster.